1. Field of the Invention
The present invention, in general, relates to soffit or foundation vents and, more particularly, to vents that close when a predetermined temperature threshold is exceeded.
Current fire codes allow for soffit types of attic vents or for foundation vents, to include a one-quarter inch mesh. This dimension is intended to keep birds or animals from entering through the vent. Soffit vents are disposed under the eaves of buildings (homes or commercial) and foundation vents are disposed through the concrete foundation walls that support a building structure.
Most homes (and some businesses) that catch on fire from wildfires that approach the structures are ignited by embers that fall either on the roof of the home (or business) or by embers which are able to enter the structure by their passage through an attic soffit vent.
Attic soffit vents allow for the passage of air and are useful in cooling the attic area during hot days or when the roof is exposed to direct sun. As such, together with warmed air they facilitate the creation of a draft. While the draft is normally desirable, during a nearby fire, the draft can permit embers to pass through the vent and ignite the structure somewhere in the attic area.
Even more troublesome, during a fire temperature differentials are apt to become excessive as ambient air is heated by the flames and this will create exceptionally powerful drafts that can convey embers through the mesh and into the attic with great force. As a result, even larger embers or other similarly sized objects that might not normally be able to pass through the mesh during a more standard amount of draft are able to enter during the increased draft produced by a fire. The strong draft is able to break apart larger embers that come in contact with the mesh and draw them into the attic space.
It is important to note that when there is the greatest amount of danger to the structure, such as during a nearby fire, the very nature of the vent which is to utilize and create draft is also increased at that time, and this capability is contrary to the needs of a homeowner because it aggravates what is already a potentially dangerous situation.
Additionally, when the structure is ignited from a location in the attic it is especially difficult, if not impossible, for firefighters to apply water to it until the entire structure has been engulfed in flames and substantially destroyed. It is much easier to detect and extinguish a glowing ember or small fire on the roof where it is both visible and readily accessible to firefighting efforts.
It is desirable to automatically close an attic vent whenever a sufficient increase in ambient temperature occurs beyond a threshold amount. In this situation, it is assumed that a fire, such as that caused by a wildfire or a nearby structure that may be ablaze, is what is elevating the temperature.
Warm air will begin to pass through the attic vent as the ambient temperature rises which will also warm the vent. As the fire approaches closer to the structure the danger of entry of a hot ember through an open attic vent also increases. Before this can occur, a significant temperature rise of the ambient air passing through the vent will have first occurred.
It is desirable to automatically close the vent if the temperature of a portion of the vent rises a sufficient amount so as to exceed a first threshold, thereby blocking the passage of air through the vent. It is desirable to again automatically open the vent when the temperature falls to below that of a second threshold, thereby again permitting the passage of air through the vent. The second threshold would include a temperature that is sufficiently far below the first threshold so as to ensure that no remaining fire danger existed.
While it may be possible to provide a self-destructing type of vent that effectively blocks the passage of air when the first threshold temperature amount is exceeded, such a device must be discarded and replaced if it is activated. This is both time-consuming and expensive.
The same need applies also for foundation vents that are used to vent crawl spaces under a structure or basement areas. Flammable materials are likely to be stored or found in either of these areas as well and the risk of entry of a hot ember also exists for foundation vents.
Accordingly, there exists today a need for a shape-memory spring activated soffit or foundation vent that helps to ameliorate the above-mentioned problems and difficulties as well as ameliorate those additional problems and difficulties as may be recited in the “OBJECTS AND SUMMARY OF THE INVENTION” or discussed elsewhere in the specification or which may otherwise exist or occur and are not specifically mentioned herein.
Clearly, such an apparatus would be a useful and desirable device.
2. Description of Prior Art
Vents, in general, are known. For example, the following patents describe various types of these devices, some of which may have relevance as well as others which may not have particular relevance to the invention. These patents are cited not as an admission of their having any particular relevance to the invention but rather to present a broad understanding of the current state of the art appertaining to either the field of the invention or possibly to other distal fields of invention.    U.S. Pat. No. 7,195,556 to Fichtelman, that issued on Mar. 27, 2007;    U.S. Pat. No. 5,711,091 to Bos, that issued on Jan. 27, 1998;    U.S. Pat. No. 5,393,221 to McNally, that issued on Feb. 28, 1995;    U.S. Pat. No. 5,167,578 to Legault, that issued on Dec. 1, 1992;    U.S. Pat. No. 4,848,653 to Van Becelaere, that issued on Jul. 18, 1989;    U.S. Pat. No. 4,597,324 to Spilde, that issued on Jul. 1, 1986;    U.S. Pat. No. 4,315,455 to Shaklee, that issued on Feb. 16, 1982;    U.S. Pat. No. 4,123,001 to Kolt, that issued on Oct. 31, 1978;    U.S. Pat. No. 3,232,205 to Bumstead, that issued on Feb. 1, 1966;    U.S. Pat. No. 2,755,728 to Frisby, that issued on Jul. 24, 1956; and    U.S. Pat. No. 2,718,187 to Frisby, that issued on Sep. 20, 1955    and including U.S. Patent Application Publication:    U.S. Publication No. 2007/0200656 to Walak, that published on Aug. 30, 2007.
While the structural arrangements of the above described devices may, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.